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United States Patent |
5,349,570
|
Kaiser
|
September 20, 1994
|
Method for operation of a radio-controlled clock and radio-controlled
clock for use in an environment subject to interference fields
Abstract
A method for operation of a radio-controlled clock comprising a
quartz-controlled clock synchronized by a time signal receiver with a time
signal via a signal processor. In a common array with an additional
device, such as a computer or television set, reception of the time signal
is generally largely prevented by the interference effect of the
additional device. In the method in accordance with the invention, the
quartz-controlled clock is therefore synchronized with the time signal
solely when the additional device is no longer generating an interference
field. For this purpose, a detector is provided that recognizes the
operating state of the additional device and permits synchronization of
the quartz-controlled clock with the time signal only when the additional
device is not generating an interference field, or if so only a reduced
one. Furthermore, a radio-controlled clock is described that is suitable
for operation by the method in accordance with the invention.
Inventors:
|
Kaiser; Reinhold (Heilbronn, DE)
|
Assignee:
|
Temic Telefunken Microelectronic GmbH (Heilbronn, DE)
|
Appl. No.:
|
102244 |
Filed:
|
August 5, 1993 |
Foreign Application Priority Data
Current U.S. Class: |
368/47 |
Intern'l Class: |
G04C 011/02 |
Field of Search: |
366/10,11,47
455/63,66,296,244
|
References Cited
U.S. Patent Documents
3590573 | Jul., 1971 | Dietsch.
| |
4419017 | Dec., 1983 | Okuyama et al. | 368/64.
|
4650344 | Mar., 1987 | Allgaier et al. | 368/47.
|
4823328 | Apr., 1989 | Conklin et al. | 368/47.
|
5083123 | Jan., 1992 | Ganter et al. | 368/47.
|
5235563 | Aug., 1993 | Ganter et al. | 368/47.
|
Foreign Patent Documents |
0258838 | Aug., 1987 | DE.
| |
54-133166 | Oct., 1979 | JP.
| |
03141728 | Jun., 1991 | JP.
| |
Primary Examiner: Miska; Vit W.
Attorney, Agent or Firm: Spencer, Frank & Schneider
Claims
What is claimed is:
1. A method for operation of a radio-controlled clock comprising a
quartz-controlled clock and a time signal receiver which receives a time
signal for synchronizing said quartz-controlled clock, said
radio-controlled clock connected in a common array with an additional
device which can have several operating states and which generates a
strong interference field in a first operating state and a reduced or
non-existent interference field in a second operating state; and wherein
said method comprises synchronizing said quartz-controlled clock with said
time signal solely when said additional device is in said second operating
state.
2. A method according to claim 1, further comprising the step of
recognizing the operating state of said additional device using a
detector.
3. A method according to claim 2, further comprising controlling said step
of synchronizing said quartz-controlled clock with said time signal by
said detector.
4. A method according to claim 3, wherein said step of controlling includes
causing no further synchronization to take place during a predetermined
time interval following the last synchronization.
5. A method according to claim 4, wherein during said step of
synchronizing, synchronization takes place following said predetermined
time interval, and when said detector has recognized said second operating
state of said additional device.
6. A method according to claim 1, wherein during said step of
synchronizing, said time signal is continuously received and evaluated
during said second operating state of said additional device.
7. A common array for controlling a radio-controlled clock, comprising:
a radio-controlled clock having a quartz-controlled clock connected to a
time signal receiver which receives a time signal for synchronizing said
quartz-controlled clock;
an additional device, connected to said radio-controlled clock, having
first and second operating states, and generating a strong interference
field during said first operating state and a reduced or non-existent
interference field during said second operating state; and
a detector, connected to said radio-controlled clock and said additional
device, for determining the operating state of said additional device, and
for allowing synchronization of said quartz-controlled clock by said time
signal only when said additional device is in said second operating state.
8. A common array according to claim 7, wherein said detector monitors an
operating voltage of said additional device.
9. A common array according to claim 8, wherein said detector allows the
synchronization of said clock by said time signal when said operating
voltage is not applied to said additional device.
Description
BACKGROUND OF THE INVENTION
The invention relates to a method for operation of a radio-controlled
clock, comprising a quartz-controlled clock and a time signal receiver
which receives a time signal for synchronizing the quartz-controlled
clock, in which the radio-controlled clock is connected in a common array
with an additional device which can have several operating states and
which generates a strong interference field in a first operating state and
a reduced or non-existent field in a second operating state.
Radio-controlled clocks are generally supplied with a time signal for
instance by the transmitter DCF-77 of Germany's Physikalisch-technische
Bundesanstalt. A first type of radio-controlled clock receives the time
signal continuously and always displays the received time. A second type
of radio-controlled clock synchronizes an autonomously operating,
quartz-controlled clock periodically with the time signal. Small,
battery-operated radio-controlled clocks in particular work according to
the second principle for energy-saving reasons. Synchronization of the
internal clock mechanism with the time signal takes place typically in the
early hours of the morning and every 24 hours, and is independent of other
factors such as the reception quality of the time signal or the strength
of the interference fields prevailing in the environment.
It is furthermore known that many electronic units in the field of signal
generation or signal processing generate interference fields that disturb
or render impossible other functions in the same unit or the functions of
equipment standing in close vicinity. This type of interference field
prohibits the operation of radio-controlled clocks in equipment such as
personal computers (PCs), television sets, video recorders etc. When
operating equipment of this type, reception of the time signal is only
possible after very high technical expenditure.
SUMMARY OF THE INVENTION
A first object of the invention is to provide a method for operation of a
radio-controlled clock that permits operation of the radio-controlled
clock in an environment subject to interference fields. This object is
attained by a method for operation of a radio-controlled clock, comprising
a quartz-controlled clock and a time signal receiver which receives a time
signal for synchronizing the quartz-controlled clock, in which the
radio-controlled clock is connected in a common array with an additional
device which can have several operating states and which generates a
strong interference field in a first operating state and a reduced or
non-existent interference field in a second operating state, and wherein
the method comprises synchronizing the quartz-controlled clock with the
time signal solely when the additional device is in the second operating
state.
A further object of the invention is to provide a radio-controlled clock
suitable for operation in an environment subject to interference fields.
This object is attained by a common array for controlling a
radio-controlled clock, comprising: a radio-controlled clock having a
quartz-controlled clock connected to a time signal receiver which receives
a time signal for synchronizing the quartz-controlled clock; an additional
device, connected to the radio-controlled clock, having first and second
operating states and generating a strong interference field during the
first operating state and a reduced or non-existent interference field
during the second operating state; and a detector, connected to the
radio-controlled clock and the additional device, for determining the
operating state of the additional device, and for allowing synchronization
of the quartz-controlled clock by the time signal only when the additional
device is in the second operating state.
An embodiment of the invention is described in detail in the following on
the basis of figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a block diagram of a first embodiment of the radio-controlled
clock in accordance with the invention,
FIG. 2 shows a second embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The array shown in FIG. 1 comprises a radio-controlled clock FU with a
quartz-controlled clock QU that is synchronized with the received time
signal by a time signal receiver ZE via a signal processor SP. The time
signal receiver ZE has an antenna suitable for reception of the time
signal. The radio-controlled clock FU forms together with an additional
device G1 a function unit, where the additional device G1 can have
operating states generating an interference field that disturbs or renders
impossible the reception of the time signal. A detector DS is provided in
accordance with the invention that recognizes this type of operating state
in the additional device G1 and, when such an operating state is present,
prevents the synchronization of the quartz-controlled clock QU with the
time signal.
In an advantageous embodiment of the invention, the detector DS is
connected to the time signal receiver ZE and suppresses the reception of
the time signal when the additional device G1 is generating strong
interference fields. The additional device G1 can be, for example, a
computer, a calculator, a PC, a mainframe, a motor vehicle or a television
set. All of these have in common the fact that they generate an
interference signal during operation that does not permit simultaneous
radio controlled operation of the radio-controlled clock. On the other
hand, none of them generate an interference signal in the switched-off
state.
In a further embodiment of the invention, the detector DS monitors the
supply of the operating voltage UB to the additional device G1.
Synchronization takes place exclusively when no operating voltage is being
supplied to the additional device which is hence in the switched-off
state. The detector comprises in this case a changeover switch that
supplies the operating voltage to the time signal receiver ZE alternately
to the additional device G1. This measure ensures that the time signal
receiver ZE can only be put into operation when no operating voltage is
being supplied to the additional device G1 and when the additional device
G1 is switched off.
In a further advantageous embodiment of the invention, the detector
comprises a wide-band radio receiver that picks up the interference
radiation generated by the additional device G1 and, above a certain
strength of said interference radiation, prevents synchronization of the
quartz-controlled clock QU by the time signal receiver ZE.
In both the above versions of the invention, it can be provided that the
next synchronization of the quartz-controlled clock QU takes place after a
fixed period since the last synchronization. This enables synchronization
to take place every 24 hours, for example. In periodic operation of the
additional device G1, synchronization of the quartz-controlled clock QU
with the time signal also takes place regularly.
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